Characterization of the heterochromatic chromosome regions in sheep (original) (raw)
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An Improved Characterization of Goat Chromosomes by Means of G- and R-band Comparison
Hereditas, 1994
An improved Characterization of goat (Capra hircus, 2n = 60) chromosomes was obtained after a Gand R-banding comparison of the prometaphase chromosomes arranged according to the standard karyotype. GTG-, GBG-, RBG, and RBA-banding made possible construction of Gaild R-banded idiograms with a common banding nomenclature. A brief G-and R-banding description of chromosomes 4, 6, 22, 23, 25, 27, 28 and 29 is also given.
Cytobios
Blood cells from 22 river buffaloes (Bubalus bubalis L., 2n =50) raised in the South Italy were cultured for both early -and late -incorporation of BrdU so as to obtain G-and R-banding, respectively. Slides were sequentially treated for Gbanding/Ag-NOR and R-banding/Ag-NOR techniques. These procedures allowed to identify which chromosomes carry the NORs and the frequency of active NORs per NO-chromosome. According to the standard nomenclature, NORs in river buffalo are located at the telomeres of chromosomes 3p, 4p, 6, 21, 23 and 24 while the frequencies of active NORs per NO-chromosome were higher in chromosomes 4p, 23 and 24 (64.8~, 70.2% and 72.2%, respectively) than in chromosomes 3p, 6 and 21 (42.1%, 17.3% and 28.1%, respectively).
Caryologia, 2003
Peripheral blood lymphocytes were cultured and treated for early-and late-BrdU incorporation to perform replicating G-and R-banding patterns, respectively. Slides were treated for GBG-, RBA-and RBG-banding techniques. Improved banded karyotypes at early-(350 bands) and pro-metaphase (500 bands) stage were performed and GBG-and RBA-banded prometaphase karyotypes were presented for the first time on this species. All chromosomes, including the small acrocentrics, show clear and distinguishable G-and R-banding patterns. Chromosome identification followed the latest chromosome standard nomenclature (ISCNH 1997). This study is also our contribution to further standard karyotype attempts at the prometaphase stage.
Comparison of RBG-banded karyotypes of cattle, sheep, and goats
Cytogenetic and Genome Research, 1991
Based on natural taxonomic criteria, the 3 main domestic species of the Bovidae family belong to 2 different subfamilies: Bovinae (Bos taurus: domestic ox or cattle) and Caprinae (Capra hircus: goat, Ovis aries: domestic sheep).
Animal Genetics, 2007
Presented herein is an updated sheep cytogenetic map that contains 452 loci (291 type I and 161 type II) assigned to specific chromosome bands or regions on standard R-banded ideograms. This map, which significantly extends our knowledge of the physical organization of the ovine genome, includes new assignments for 88 autosomal loci, including 74 type I loci (known genes) and 14 type II loci (SSRs/microsatellite marker/STSs), by FISHmapping and R-banding. Comparison of the ovine map to the cattle and goat cytogenetic maps showed that common loci were located within homologous chromosomes and chromosome bands, confirming the high level of conservation of autosomes among ruminant species. Eleven loci that were FISH-mapped in sheep (B3GAT2, ASCC3, RARSL, BRD2, POLR1C, PPP2R5D, TNRC5, BAT2, BAT4, CDC5L and OLA-DRA) are unassigned in cattle and goat. Eleven other loci (D3S32, D1S86, BMS2621, SFXN5, D5S3, D5S68, CSKB1, D7S49, D9S15, D9S55 and D29S35) were assigned to specific ovine chromosome (OAR) bands but have only been assigned to chromosomes in cattle and goat.
Y chromosomal characterization of Turkish native sheep breeds
Livestock Science, 2011
In this study, ten native Turkish sheep breeds were sampled to evaluate Y chromosomal genetic variation. Two regions of the SRY gene, one region each of the DBY and AMEL genes and SRYM18 Y-specific microsatellite locus were sequenced. While no base substitutions were found in the sequenced regions of SRY, DBY and AMELY, most of the Turkish sheep breeds have some variations of SRYM18. In total, we found three different SRYM18 alleles that were 141, 143 and 145 bp in length. The distribution of these alleles was different among fat-tailed sheep breeds and the thin-tailed sheep breeds. While the most common allele was 143 bp among the breeds, the 141-bp allele was also observed in both fat-tailed and thin-tailed breeds. The 145-bp allele was only found in the fat-tailed sheep at low frequency.